Scientists Reconstruct Ancient Plague That Killed More Than 50 Million People

Germany-based researchers were able to reconstruct the deadly Justinian plague that killed off almost 15 percent of the world's population throughout the Byzantine Empire. The researchers were also able to pinpoint the bacterium responsible for the death of approximately 50 million people.

Their findings, published in the journal Molecular Biology and Evolution, suggests that the bacterium, known as Yersinia pestis, that wreck havoc during the Justinian plague between the 6th and 8th centuries BCE is the same one that is responsible for the Black Death during the 1300s.

"Our research confirms that the Justinianic plague reached far beyond the historically documented affected region and provides new insights into the evolutionary history of Yersinia pestis, illustrating the potential of ancient genomic reconstructions to broaden our understanding of pathogen evolution and of historical events," explained research colleague Michal Feldman in a statement.

For the study, the researchers generated the first high-coverage genome of the bacterial agent responsible for the Justinian plague using the DNA of Yersinia pestis recovered from sixth century skeletons in Altenerding, an ancient southern German burial site near Munich.

Their new sequence of the Yersinia pestis bacterium revealed 30 newly identified mutations and structural rearrangement unique to the Justinian strain, in addition to correcting 19 false positive mutations. Three of those are located in nrdE, fadJ and pcp genes, which are critical to the plague's ability to make people sick.

Their study suggests that the strain of the bacterium is more genetically diverse than what is previously thought. The researchers were still baffled how and why the pathogen disappeared in the 8th century, only to re-emerge in Germany in the 1300s.

With the help of these findings, researchers could now have an important historic, high-quality reference resource that can be used to analyze the key evolutionary changes, adaptation and human impact of plague, which is considered to be a re-emerging infectious disease in certain regions.